New Jersey Butterflies

White M Hairstreak

Parrhasius m-album

Identification: Very small—but our largest hairstreak (just a bit larger than Coral and Acadian). Almost never seen with wings open. Above: FW and HW bright, iridescent blue that can be seen when the butterfly flies or rubs its wings back and forth. Below: Gray with distinct white line bordered with black across both wings. Line forms an obvious "M" near tails. Large red-orange spot on HW is set inward away from margin, and neighboring blue spot lacks an orange cap. When fresh a single white dot (or dash) near leading edge of hindwing is distinctive. Similar hairstreaks: Oak Hairstreak is dark above, usually lacks the isolated white mark near the leading edge of the HW below, and orange spot near HW tails is not set inward from the margin. Gray Hairstreak is gray below (but may appear brown when heavily worn), the postmedian bands include orange (and usually do not form as conspicuous an "M"), the orange spot at HW tails has a black spot outwardly, and usually a thin black line across the inner side.

NJ Status and Distribution: Resident. Generally uncommon to rare but occasionally fairly common in South Jersey

NJ Range Map-White M Hairstreakk

Habitat: Open areas with flowers near woods with oaks.

Flight Period: Late April to mid-October. Extreme dates: North Jersey 4/13—10/13; South Jersey 3/30—11/9.

Larval Food Plants: Oaks (Quercus).

Overwintering Stage: Pupa.

Best Locations: Higbee Beach WMA, Belleplain SF, Dennis Creek WMA, Crater Lake Rd., Glassboro WMA

Comments: Likes to nectar on milkweeds, dogbanes, sedums, and Chinese Lespedeza (Lespedeza cuneata)—the last an alien, highly invasive species. Always a good find. Watch for that flash of blue when it flies!



White M Hairstreak

New Vernon, Morris Co., NJ, 9/7/07, on goldenrod.